(CNN) -- The average man probably does not consider saving wildlife when popping a dose of Viagra, but two scientists suggest that the tiny pill could save tens of thousands of animals.

Endangered animals such as seals and tigers have been hunted for thousands of years for their presumed healing qualities in traditional Chinese medicine.

Traditional Chinese medicines often rely on specific body parts from certain kinds of animals to treat common physical ailments, such as erectile dysfunction.

The harvesting of at least three species used in traditional impotence remedies dropped considerably during the late 1990s, coinciding with booming sales of Viagra, according to Frank von Hippel, a
biologist at the University of Alaska in Anchorage, and his brother William, a psychologist at University of New South Wales in Sydney, Australia.

The pair attributes some of the decline to the popular drug, but some wildlife activists remain skeptical of the link.

Jan Vertefeuille, a representative of the World Wildlife Fund (WWF), said other popular Western drugs have not had an impact on traditional Chinese medicines.

"If that were the case, the demand for tiger bone, which helped make the species so endangered, would have dropped with the advent of aspirin," he said. Ground-up tiger bone is used in traditional
Chinese medicine as a pain reliever.

Cao Dan, a specialist in Chinese medicine with the WWF, said there is widespread Asian suspicion toward many Western remedies like Viagra.

"One of the reasons for this strong hesitancy to Western medicine is concern about side effects," she said. Viagra, for instance, has caused cardiac problems in a number of its users.

Harvested animal parts are typically sold as manufactured extracts rather than as whole, unprepared products. Since the trade of endangered animals is illegal, the von Hippels studied data on the legal
export from Canada of fur seal, harp seal and reindeer.

"They are a proxy for what is probably happening to the trade in illegally-traded species," said Frank von Hippel.

Traditional Chinese remedies prize the velvet of reindeer and the genitals of male seals because they are said to enhance sexual performance.

Commerce in all three items plummeted in recent years, according to the von Hippels. From 1997 to 1998, antler velvet sales fell 72 percent from $700,000 to $200,000. In 2000, only 10 Hooded seals
were killed in Canada out of an allowable catch of 10,000.

In 1998, an estimated 20,000 Harp seal organs were sold at an average price of $20. In years past, each would fetch up to $115. In 1999 and 2000, there has been "virtually no market for seal organs," the
Canadian Department of Fisheries and Oceans reported.

Impotence is not a primary focus in traditional Chinese medicine, but the price that men are willing to pay for a cure is significant. And Viagra is an attractive alternative because of its low price and
availability, according to the von Hippels.

Some conservationists think that there are better explanations for the sluggish trade in a handful of Canadian animal parts. Seals can be harvested for organs other than their genitalia, they say. Moreover,
the decline in animal part exports from Canada coincided with the economic meltdown in much of Asia.

The von Hippels, who published their findings in the September edition of the journal Environmental Conservation, acknowledge that other factors contribute to the decline in sales of these species. But
they plan to keep monitoring data on the three animals and are on the lookout for new indicator species.